Sprocket run out - ~1mm excessive?

[andyharding]

As some of you may have read on my previous thread my bike has failed the dredded mot on excessive run out on the rear brake disc. I have replaced the disc and thought all would be fine.

Now i have noticed that when the bike is on the rear stand and in first gear the wheel is just spinning nicely, the rear srocket looks to be buckeled. It is moving from side to side around 1mm on every rotation.

Is this normal or is my rear sprocket buckeled to. Does anyone elses do this. I have the bike in for a re test tomorrow and dont want it to fail again.

Please help or advise. Urgent responce would be fantastic.

Cheers in advance

[SAMMY650]

Hi,

I've never had that problem with the sprocket on my Sv650 2000 and i've never heard anyone else say they've had it happen so I would imagine that your sprocket is buckled(sorry). Supersprox are supposed to be quite good.

[Stig]

You have fitted the spacer back in right?

[Philbo]

I'm not a mechanical guru, but 1mm of movement doesn't sound like much... :-k

[andyharding]

You have fitted the spacer back in right?

Yeah everthing has gone in the way it was.

Am i right in saying that on my mot fail certificate it only says "Rear brake disc has excessive run out". Am i right in thinking that it should only be a partial test when i go back. So does that mean he will only check the disc.

[Dangerous Dave]

Am i right in thinking that it should only be a partial test when i go back. So does that mean he will only check the disc.
Officially it should be a full test again, two things;

1) Is the wheel in straight, chain adjusters equal on both sides?

2) Does the rim of the wheel seem to do the same thing when spun?

[andyharding]

Officially it should be a full test again, two things;

1) Is the wheel in straight, chain adjusters equal on both sides?

2) Does the rim of the wheel seem to do the same thing when spun?


Yeah adjusters are bang on equal. The wheel runs perfect. Its like its fine for two or three revs then its wobbles. then ok for two or three revs then wobbles again.

[Dangerous Dave]

Sure its the sprocket wobbling and not your head??? :shaking:

Check the rear bearings.

[tigersaw]

Sounds like the chain has a tight spot, and is straining the sprocket as that bit comes round. Loosen it off a bit.

[sinbad]

Does the new rear disc "move" in the same way?

[andyharding]

Does the new rear disc "move" in the same way?

No the rear disk is perfect. Any way its passed the MOT. the guy said not to worry about the sprocket. Every sprocket wobble. Just some more than others and the faster you go the more it wobbles. Its all down to the tollerences in the manufacturing process of the bike between the clutch, front sprocket and rear sprocket.

He said its perfectly fine and its nothing to worry about.

By the way my Failed disc had 0.2mm of runnout the absolute minimum it can be before a fail. Gutted.

[Tim in Belgium]

My rear sprocket has a slight "wobble" nothing that I'm concerned about, it's been like that for almost 3 years....

[-Ralph-]

My rear sprocket has a slight "wobble" nothing that I'm concerned about, it's been like that for almost 3 years....

Mine too, regardless of chain tension. Never caused a problem.